I saw a short video of this experiment on Reddit and thought it would be an interesting science experiment to try with the kids.
Here is our recreation of the experiment:
Step 1: Materials
Below is a list of the materials you will need for the experiment.
- Tall Glass with a slightly larger diameter than the candle
- Food Coloring or Mio
- Spoon (Optional)
Step 2: Add Food Coloring to Water
You can do the experiment with just water but colored water is easier to see. We used Mio instead of food coloring.
Step 3: Add Colored Water to Plate
You should experiment with different levels of water. We used about 1/4".
Step 4: Place Candle in Center of Plate
Candle should be placed vertical as shown.
Step 5: Light Candle
Light the candle. Note that a larger flame gives a more dramatic effect.
Step 6: Place Glass on Candle
Carefully place the glass container over the candle.
Step 7: Watch the Science in Action
I tried to grab some frames of the process. Notice how the colored water moves from the plate into the glass container. Once the candle flame goes out, you will see an inrush of water.
If you search for this on the web, you will see multiple ideas on how it works.
I took the explanation of Oliver Knill from the Harvard Math Department. He states in general terms: "The candle heats the air and expands it. This cancels the depletion of the oxygen temporarily and the water level stays down. When the oxygen is depleted, the candle goes out and the air cools. The volume of the air decreases and the water rises. The temporary temperature change delays the rise of the water"
For debate on the subject, see the following link: